Cordyceps sinensis (c. sinensis) extracts have been used by Chinese people for many centuries as a part of traditional Chinese medicine, and is purported to have broad nutritional health benefits. C. sinensis is a parasitic fungus which grows by attaching to and feeding from one of several species of moth caterpillar living about six inches underground in the Tibetan plateaus. The fruiting body of c. sinensis is typically black and somewhat resembles the host body in appearance.
In 1993, c. sinensis was used as an integral part of the winning Chinese women's track team's diet regime. Since that time, the demand for c. sinensis has risen sharply. However, since the cultivation and harvest season for c. sinensis is only during late spring and fall of each year, demand continues to outweigh supply, and continuing research and development efforts have been hindered.
C. sinensis is reported to have a number of specific health imparting benefits, including anti-oxidant, anti-viral, anti-tumor, and anti-fatigue properties, as well as aiding in the treatment and prevention of hyperglycemia, renal dysfunction, liver disease, and in stimulation of immune, cardiovascular, respiratory, and reproductive responses. See, Zhu, Halpern, and Jones, “The Scientific Rediscovery of an Ancient Chinese Herbal Medicine: Cordyceps sinensis, Part I” The Journal of Alternative and Complementary Medicine, Vol. 4, pp. 289-303 (1998), and Zhu, Halpern, and Jones, “The Scientific Rediscovery of an Ancient Chinese Herbal Medicine: Cordyceps sinensis, Part II” The Journal of Alternative and Complementary Medicine, Vol. 4, pp. 429-457 (1998), incorporated herein by reference.
Many different fungi have been reportedly isolated from c. sinensis. However, there has been considerable dispute over the correctness of these reports, and the exact source of all reported fungi. Additionally, there has been much confusion as to the relationship and action between the various fungi found in the mycelium of c. sinensis. 
In view of the truncated cultivation and harvest season for c. sinensis, a number of artificial culturing efforts have occurred. While such efforts have been moderately successful, it is now believed that cultured c. sinensis is less potent than the natural product.
In view of the foregoing, additional information concerning the characterization and relationship of the various fungi in c. sinensis mycelia, as well as methods for artificially reproducing such fungi which have the potency of naturally obtained fungal products continues to be sought.